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Grit profile

100grit sandpaper

Medium

Smoothing rough wood. Last grit before primer in most paint prep.

100 grit in other scales

If the pack says 100 (CAMI, most US paper)

~140 µmBetween P100 and P120.

If it says P100 (FEPA, Festool, Mirka, Norton 3X)

~162 µmBetween CAMI 80 and 100.P100, converted →

Sizes are average particle diameters from the published CAMI and FEPA tables. Full ladder in the grit chart; any grade on any scale in the grit converter.

What 100 grit is for

100-grit smooths what 80 left behind. It’s the workhorse grit for general DIY: rough enough to remove tool marks, fine enough that 150 or 180 takes over for finishing. For paint prep on already-painted surfaces, 100 is often the only grit needed.

Projects at 100 grit

  • · Smoothing milled lumber for paint
  • · Pre-priming repaired drywall
  • · Scuff-sanding old cabinets before repainting
  • · Smoothing edges on plywood projects
  • · Light shaping on softwood

Abrasive materials

  • · aluminum oxide
  • · ceramic
  • · garnet (for fine woodwork)

Common mistake

On bare hardwood headed for stain, 100 alone is too coarse: keep climbing to at least 150 or 180.

← 80 grit (the step before)120 grit (the step after) →

Top pick at 100

3M Pro Grade Precision Assorted Pack

Five grits. One box. Everything you need to finish what you started.

Check priceReview

Catalog fit

100

Current SKU matches in this grit lane.

Common forms

5

Forms represented here, led by discs.

Head to head

4

Comparison pages currently touching this stage of the sanding climb.

Use this grit when

The surface still needs this stage.

  • · Smoothing rough wood. Last grit before primer in most paint prep.
  • · This is the working middle of most sanding progressions: enough bite to matter, refined enough not to leave the job stranded.
  • · On this site, 100 grit shows up most around paint prep, 3×21 belt sanders, metal finishing, and 6-inch orbital sanders.

Skip this grit when

The job is earlier or later than this.

  • · Skip this grit if you still need heavy stock removal or if the surface is already ready for polish-level refinement.
  • · Skip the urge to jump straight here from a very coarse grit; the scratch pattern underneath will usually survive the shortcut.

Recommended at this grit.

Head to head

Comparisons in this lane.

Norton 3X Sheet Sandpaper, 220 Grit (20-pack) vs. 3M Pro Grade Precision Assorted Pack

One grit done right, or five grits done well.

Read the breakdown →

Mirka Gold 5-inch Hook & Loop Disc Assortment vs. Diablo 5-inch ROS Discs, 120 Grit (50-pack)

Finnish precision or American volume.

Read the breakdown →

3M 9×11 40-Grit Sandpaper (5-pack) vs. Norton 3X Sheet Sandpaper, 80 Grit (20-pack)

How rough is the surface, and how much do you want left of it.

Read the breakdown →

3M Pro Grade Precision Assorted Pack vs. Gator Finishing Multi-Grit 9x11 Sandpaper Pack

Both cover the range. One holds up longer.

Read the breakdown →

Questions people ask

The practical part.

What is 100 grit actually for?

100 grit is for smoothing rough wood. last grit before primer in most paint prep. This is the working middle of most sanding progressions: enough bite to matter, refined enough not to leave the job stranded.

What should come before and after 100 grit?

The safe lane is usually 80 -> 100 -> 120. You can stretch that a little on easy material, but large jumps usually leave scratches behind.

Which forms make the most sense at 100 grit?

On UltraRough, this grit shows up most in discs, belts, and sheets. That reflects where shoppers usually need this cut level in the real world.

Keep moving

Follow the climb.

80 gritThe step before 100 grit.120 gritThe next step after 100 grit.DiscsSee discs that commonly show up in this lane.BeltsSee belts that commonly show up in this lane.SheetsSee sheets that commonly show up in this lane.Use the grit selectorStart from the project instead of the number.Sandpaper grit chart: coarse to fineThe full range mapped to projects — every grit from 40 to 3000.Find the right grit for your projectTell us the job; we'll tell you where to start and where to stop.
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